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Here's another "Thanks, Healey Nut" for the tip on Snoop. Never heard of it, but it sounds good. And I agree with those that say the H-10 is just the first step of leak detecting. Follow up with soap (soon to be Snoop). Also, on the bigger stuff, I agree with "no bubbles, no problems". After all, what's a half ounce per year when the charge is hundreds, or thousands of pounds?

As a side note... You really need to read the MSDS on R123 refrigerant. Bad thing have been known to happen in the state of California with that particular type of refrigerant. Get yourself a respirator with good chemical filters and make sure there is a full time working leak detector in the room.

As a side note... You really need to read the MSDS on R123 refrigerant. Bad thing have been known to happen in the state of California with that particular type of refrigerant. Get yourself a respirator with good chemical filters and make sure there is a full time working leak detector in the room.

...Ron

Yup. Nasty stuff. I haven't set up a room leak sniffer for 123 in a few years, but remember the ppm setting was way, way lower than other regrigerants.

As a side note... You really need to read the MSDS on R123 refrigerant. Bad thing have been known to happen in the state of California with that particular type of refrigerant. Get yourself a respirator with good chemical filters and make sure there is a full time working leak detector in the room.

Please elaborate regarding the state of California. From everything I've read it's not much worse than R-11. The exposure limits to cause serious harm are much higher than one would think. Read the MSDS from DuPont. Testing levels for inhalation for rats was 32,000 ppm! And 19,000 ppm for dogs. Sheez, in a well ventilated room those kinds of concentrations are not going to be realized.

That's a sales tactic that Carrier uses to try to scare the building owners into not buying R123 chillers and buying the less efficient R134A chillers. They also tell their techs that's it's nasty stuff so they spread that propaganda around.

That's a sales tactic that Carrier uses to try to scare the building owners into not buying R123 chillers and buying the less efficient R134A chillers. They also tell their techs that's it's nasty stuff so they spread that propaganda around.

The refrigerant detection panel manufacturers must be in on it as well then, one manual suggests 1000ppm for R11 and R134A but 50ppm for 123A.

You know, I really don't know about the subject other than having to set the sniffer alarm threshholds, so I went looking, and found these blurbs at epa.gov. From this it would indeed seem that R123A is more toxic than R134A, but the limits seem to be chosen to be very conservative. Apparently critical body parts will not fall off with just a sniff....

Here is what I found:

R-123 Toxicology

Tests of R-123 indicate that it has very low acute inhalation toxicity, as measured by the concentration that causes 50% mortality in experimental animals, a 4-hour LC50 of 32,000 ppm in rats. A cardiac sensitization response was observed at approximately 20,000 ppm. This response was measured in experimental screening with dogs, with simultaneous injection of epinephrine to simulate human stress reactions. Anesthetic-like effects (e.g., weakness, disorientation, or incoordination) were observed at concentrations greater than 5,000 ppm, or 0.5%. R-123 has very low dermal toxicity (by skin application) and is only a mild eye irritant. Long-term inhalation caused an increase in the incidence of benign tumors in the liver, pancreas, and testis of rats. None of the tumors attributable to the exposures were malignant or life-threatening; all occurred near the end of the study, late in the lives of the test specimens. The exposed animals actually exhibited higher survival rates at the end of testing than those in the control group. The rats exposed to higher concentrations also experienced slight reductions in body weight and decreases in cholesterol and triglyceride levels. Studies are continuing to investigate the biological relevance of the tumors to humans. The tests completed to date indicate that R-123 is neither a developmental toxicant nor a genotoxin.

Based on the findings of extensive testing, R-123 has been deemed to have low toxicity. Refrigerant manufacturers recommend that long-term, occupational exposures not exceed limits of 10 and 30 ppm, on eight-hour time-weighted average (TWA) bases. One manufacturer suggests a limit of 100 ppm, also TWA, but is expected to revise this recommendation to somewhere in the 10-30 ppm range. The differences in recommended limits stem from conservative interpretation of the data. As discussed below, occupational exposures can be held well below even the most stringent of these recommendations.

The exposure limits are based on chronic toxicity concerns and are below those at which toxic effects were observed in the laboratory tests. Higher concentrations are allowable for short-periods, but exposures still should be kept to the minimum practicable, as for all chemicals.

R-134a Toxicology

R-134a also has very low acute inhalation toxicity. The lowest concentration that causes mortality in rats, the 4-hour Approximate Lethal Concentration (ALC), exceeds 500,000 ppm. The cardiac sensitization response level for R-134a is approximately 75,000 ppm. Anesthetic-like effects are observed at concentrations greater than 200,000 ppm, or 20%. Long term exposures with very high concentrations, 50,000 ppm, caused an increased incidence of benign tumors in the testis of rats. Again, none of the observed tumors were life-threatening, and all occurred near the end of the study. The evidence from all tests in cultured cells or organisms, as well as in laboratory animals, indicates that R-134a in not genotoxic and that the increased incidence in benign tumors is not due to an effect on genetic material.

The test findings indicate that R-134a has very low acute and subchronic inhalation toxicity, is not a developmental toxicant, and is not genotoxic. Most refrigerant manufacturers recommend that TWA occupational exposures not exceed 1,000 ppm; this also is the level recommended by the American Industrial Hygiene Association, Workplace Environmental Exposure Limit (WEEL) Committee. Again, exposures still should be kept to the practicable minimum.

It is important to note that the tumors attributable to the R-123 and R-134a exposures were not cancerous. The findings reflect an increase in tumor incidence compared to rats in the experimental control group, those not exposed to the refrigerants. Some tumors also were observed in this control group, but not as many. Also, the recommended occupational exposure limit for each refrigerant is below the level at which toxic effects were observed in laboratory animals. The use of rats, dogs, and other animals is based on accepted scientific procedures and sensi- tivities to specific concerns by species. The lower exposure limit affords both a margin of safety and a conservative reflec- tion of potential differences, between responses in individual humans and between humans and test animals.

When a 123 chiller springs a leak, depending where the leak is, it will suck in air. If its on the high side, its only a couple PSI over atsmopheric. High pressure chillers will dump a hell of alot of refrigerant through the same size hole.